Examinations on the self-healing capacity of geosynthetic clay liners

Abstract The objective of this paper is to evaluate the self- healing properties of a commercially-available geosynthetic clay liner (GCL) using flexible-wall permeameter. The GCLs are produced by the same factory, but the contents of bentonite are different. Also the hydraulic conductivities (HC) of GCLs with no defect are different. In this study, specimens were completely saturated under the backpressure of 20 kPa before the test. Permeability tests were performed on GCL specimens with penetrating flaw and also on specimens permeated with distilled water and CaCl2 solutions. The test results were presented and discussed. Experimental results showed that the GCL with penetrating flaw did not exhibit complete self-healing in the case of flaw. After 120 days, the hydraulic conductivity increased by approximately an order of magnitude. In addition, CaCl2 solutions had a significant influence on the hydraulic conductivity. The research findings might be of interest to researchers and engineers who design liners for landfills and other liquid containment facilities

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Kaolin based protective barrier in municipal landfills against adverse chemo-mechanical loadings

Scientific Reports ◽

10.1038/s41598-021-89787-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Partha Das ◽

Tadikonda Venkata Bharat

Keyword(s):

Ionic Strength ◽

High Ionic Strength ◽

The Self ◽

Design Parameters ◽

Layered System ◽

Geosynthetic Clay Liners ◽

Clay Liners ◽

Landfill Liner ◽

First Time ◽

Applied Stresses

AbstractIn this work, we assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste. The laboratory permeation tests with high ionic strength salt solutions reveal that the GB fails to seal and exhibits a significant mechanical collapse under different applied stresses. The applicability of GB in the form of geosynthetic clay liners as the bottom liner facilities in landfills that produce high ionic strength salt leachates, therefore, remains a serious concern. We propose an additional barrier system based on kaolin, for the first time, to address this problem. The proposed kaolin-GB layered system performs satisfactorily in terms of its sealing and swelling ability even in adverse saline conditions and low overburden stresses. The kaolin improves the osmotic efficiency of the self and also helps the underlying GB layer to seal the inter-granular voids. The estimated design parameters by through-diffusion test suggest that the kaolin-GB layered system effectively attenuates the permeant flux and suitable as a landfill liner.

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Self-Healing Properties of Geosynthetic Clay Liners

Geosynthetics International ◽

10.1680/gein.8.0203 ◽

2001 ◽

Vol 8 (5) ◽

pp. 461-470 ◽

Cited By ~ 30

Author(s):

G.L. Sivakumar Babu ◽

H. Sporer ◽

H. Zanzinger ◽

E. Gartung

Keyword(s):

Self Healing ◽

Geosynthetic Clay Liners ◽

Clay Liners

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Insights into Desiccation and Self-Healing of Bentonite in Geosynthetic Clay Liners under Thermal Loads

E3S Web of Conferences ◽

10.1051/e3sconf/20199203006 ◽

2019 ◽

Vol 92 ◽

pp. 03006

Author(s):

Abbas El-Zein ◽

Bowei Yu ◽

Ali Ghavam-Nasiri

Keyword(s):

Hydraulic Conductivity ◽

Mechanical Model ◽

Thermal Gradients ◽

Self Healing ◽

Transient Phase ◽

Geosynthetic Clay Liners ◽

Clay Liners ◽

Sodium Bentonite ◽

Mechanical Loads ◽

Numerical Investigations

Geosynthetic Clay Liners (GCLs) are widely used for protecting groundwater from pollution sources at the surface, including applications in which they are subject to significant thermal gradients. Hence, sodium bentonite in the GCL may undergo significant dehydration and cracking, and the GCL might fail as a result. The paper presents outcomes of a set of recent experimental and numerical investigations exploring the propensity of bentonite to desiccate and self-heal, as well as means of mitigating the effect of thermal gradients on the hydraulic conductivity of GCLs. An elasto-plastic thermo-hydro-mechanical model was found to yield reasonable predictions of experimental behaviour, except for the transient phase of pre-heating hydration. Introducing an airgap between the GCL and the heat source can reduce the extent of desiccation and its effects on hydraulic conductivity. However, the effectiveness of the solution will depend on other factors including subgrade, magnitude of thermal and mechanical loads and type of GCL.

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Shrinkage Curves for Powder and Granular Bentonites

E3S Web of Conferences ◽

10.1051/e3sconf/20199207009 ◽

2019 ◽

Vol 92 ◽

pp. 07009

Author(s):

Martin Wijaya ◽

Eng Choon Leong ◽

Hossam Abuel-Naga

Keyword(s):

Volume Change ◽

Low Permeability ◽

Self Healing ◽

Geosynthetic Clay Liners ◽

Clay Liners ◽

Swelling Properties ◽

Shrinkage Curve ◽

Shrinkage Behaviour ◽

Different Types ◽

Surrounding Soil

Bentonite is one of the most commonly used materials in geotechnical engineering applications especially for isolation purposes due its low permeability and its highly expansive nature. For instance, Geosynthetic Clay Liners (GCL) self-healing ability relies on the swelling properties of the bentonite to close any holes in the GCL while the low permeability of the bentonite serves to reduce the infiltration of leachate to the surrounding soil. However, different types of bentonite have different shrinkage or swelling properties and hence affects the effectiveness of the GCL. A method to assess the wetting/drying induced volume change of the bentonite is through its shrinkage curve. This paper focuses on the shrinkage behaviour of reconstituted granular and powder bentonites which are used in GCL. Photogrammetry method is used to measure the volume change of specimen during drying. The shrinkage curves of the bentonites are then compared with other bentonites from the literature.

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